Emergency Tax Code in the UK: What It Means and How to Fix It (2026)

When you start a new job in the UK without a P45 from a previous UK employer — which is the case for almost every immigrant — HMRC puts you on an emergency tax code. This means you pay more income tax than you should, sometimes significantly more. The good news: it is fixable and you can reclaim every penny of overpaid tax.

What do the emergency tax codes mean?

• 1257L W1 or 1257L M1 — you get a personal allowance (£12,570/year) but it is calculated week by week or month by month instead of for the full year. You pay more tax than you should early in the tax year.
• BR — "Basic Rate" — all your income is taxed at 20% with no personal allowance at all. Very common for immigrants starting their first UK job.
• OT — no personal allowance, and higher earners pay higher rates on everything. Rare but possible.
• 0T — similar to OT, no personal allowance. Often assigned when HMRC has no information about you at all.

Why does this happen to immigrants?

When you change jobs in the UK, you give your new employer a P45 (a leaving document from your previous employer). HMRC uses this to assign the right tax code. If you are new to the UK, you have no P45 — so HMRC defaults to an emergency code until they can confirm your situation. It is not a penalty; it is just a temporary holding position.

How to fix it — step by step

• Step 1: Tell your employer you have no P45 and ask them to submit a P46 (Starter Checklist) to HMRC on your behalf — tick Box C ("this is my first job since leaving full-time education" or "I have another job/pension") depending on your situation
• Step 2: Register for a Personal Tax Account at gov.uk/personal-tax-account — this lets you see your tax code and request changes directly
• Step 3: Contact HMRC on 0300 200 3300 (Monday–Friday, 8am–6pm) and tell them you are new to the UK, you have no P45, and you believe your tax code is wrong
• Step 4: HMRC will update your tax code — your employer will receive the new code automatically and adjust your future payslips
• Step 5: Any tax you overpaid should be refunded automatically through your payslip once the correct code is applied

How to reclaim tax you have already overpaid

Once HMRC corrects your tax code, any overpaid tax from the current tax year (April to April) is usually refunded through your payslip automatically — your employer applies a negative tax deduction until the balance is zeroed. If the tax year has already ended, HMRC will send you a P800 tax calculation letter and refund you directly, or you can claim through your Personal Tax Account.

Can I reclaim overpaid tax from previous years?

Yes — HMRC allows you to claim overpaid tax going back 4 years. If you were on an emergency tax code for months or years without realising, contact HMRC directly or complete a Self Assessment tax return for the relevant years. You may be owed hundreds or even thousands of pounds.